Ventilating apparatus



H. F. SCHMIDT. VENTILATING APPARATUS. APPLICATION FILED JULY 13,1914. 4

1,345, 38, Patented July 6, 1920.

y x /5 6 a /2 /0 7 M H y f 3| I I' I I 1 Hi! Ii i H F! i I 5 WITNESSES:INVENTORS y H 56mm Wm BY ATTORNEY UNITED STATES PATENT OFFICE;

HENRY F. SCHMIDT, 0F PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSEELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

VENTILATING APPARATUS.

Specification of Letters Patent.

Patented July 6, 1920.

Application filed July 13, 1914. Serial No. 850,804.

and State of Pennsylvania, have invented a new and useful Improvement inVentilating Apparatus, of which the following is a specification.

My invention relates to ventilating and cooling apparatus, and it hasspecial reference to ventilating devices adapted for use in connectionwith dynamo-electric machines, such as high-speed turbo-generators andthe like.

The object of my invention is to provide ventilating apparatus whereby alarge volume of air or other ventilating or cooling fluid is positivelyforced into the space to be ventilated or cooled by means of animpelling fan or blower of relatively small dimensions.

The single figure of the accompanying drawing is a longitudinalsectional ,view of a portion of'a turbo-generator equipped with aventilating device embodying my invention. I

Large dynamo-electric machines, such as turbo-generators, especiallysuch machines as are provided with closed end casings, generate moreheat than can. be dissipated by the currents normally set up by therotating mechanism, and fans or blowers are therefore commonly employedfor the purpose of forcing additional air through such machines.

However, the high peripheral speed at which many of these machines aredriven renders it impossible to make the ordinary centrifugal blowerslarge enought'o supply the necessary volume of air, although high airpressure is readily obtained. I have taken advantage of this latterfact, and succeeded in supplying a large amount of air with the use ofrelatively small fans, by conducting the air discharged by the fanthrough a narrow passage or whirl-chamber, of rapidly decreasingtransverse section, into which opens a bypass channel. The blast fromthe fan draws additional air through this by-pass channel, on thewellknown principle of the steam injector.

The apparatus illustrated as embodying my invention may be equally welldescribed as consisting of a rotatable impeller, a whirl chambersurrounding the impeller and receiving the fluid discharged therefrom, asecond whirl chamber surrounding the first chamber andreceiving fluiddischarged from the first chamber, and'an inlet for the admission offluid into the second whirl cham ber. By so describing the apparatus, Iconsider the so-called by-pass channel in its broadest sense, that is,merely as an opening for the admission of fluid into the second whirlchamber; in addition to this I consider this inlet or opening asdividing the whirl chamber into two whirl chambers, the firstsurrounding the impeller and the second surrounding the first.Considering the apparatus in this way the operation may be described asfollows: The velocity energy of the fluid discharged from the impelleris partially converted into potential energy as the fluid traverses thefirst whirl chamber. Inasmuch as the outletof the first whirlchambercommunicates with a region of the same or approximately the samepressure as that of the main inlet to the propeller, the first whirlchamber will preferably be so designed as not to increase the pressureof the fluid materially above the pressure existing at the inlet oradmission opening. The principal function of the first whirl chamber istherefore to prevent an abrupt building up of pressure immediatelyadjacent to the outlet of the propeller and a consequent loss of energydue to shock. The fact that the'pressure of the fluid issuing from thepropeller is gradually increased materially increases the efiiciency ofthe-impeller, since the gradual conversion ,of the velocity energy ofthe fluid leaving the impeller into pressureenergy increases the flow offluid through the impeller. The fluid issues from the first whirlchamber at a high velocity and in the form of an annular or disk shapedwhirling jet. This jet in passing to the second chamber is exposed to,and consequently entrains fluid admitted through the inlet or. admissionopening between the two whirl chambers. The velocity energy of the diskshaped jet and the fluid entrained by it is converted into potentialenergy as represented by the increase in pressure as the fluid mixturepasses through the second whirl chamber. In the apparatus illustratedthe second whirl chamber delivers fluid to the cooling or ventilatingpassages of the apparatus to be cooled.

For a better understanding of my invention, reference may be had to thedrawing, which shows portions of the rotor l and the stator 2 of aturbo-generator, the end turns 3 of the stator windings being inclosed,in the usual manner, in the cylindrical casing 1-, one-half of which isshown in the drawing. The shaft 5 of the rotor 1 carries an annularsupport 6, upon which is mounted a centrifugal fan or impeller 7 thatrotates with the shaft An air chamber 8, communicating with the outeratmosphere, is connected by a channel 9 to the inlet of the impeller 7,and the air delivered by the impeller is received in an annular channelor whirl-chamber 10, of rapidly decreasing width, formed by an- 11 and12 surround tne shaft 5 in the relation shown, and are secured, in anysuitable manner, to the walls of the casing 4;. The whirl-chamber 10, atnarrowest part 153, communicates with a bypass channel 1 by whichconnection is made between the channel and the air chamber 8. From thepoint of union between the bypass channel and the throat 18 of thewhirl-chamber 10, the partitions 11 and forma second whirlchamber 16,which, as shown has parallel sides and which communicates with thecasing a through the opening 17.

l t will be observed that an acute angle is formed by the whirl chamber10 and the channel 14, and that the air chamber 8 is suiliciently largeto supply both the inlet 9- to the tan and the by-pass channel 1%. willalso be readily understood that the air delivered by the blower 7 iscompressed in the whirl-chamber 10 and passes the narrow throat 13 atrelatively high velocity. The strong air blast thus produced tends toform. a vacuum in the bypass channel 1%, and thus draws a considerablevolume of air through this channel;

it will be observed that the kinetic energy of the whirling air blastgenerated by the centrifugal fan is utilized directly, in draw- "ingadditional air through the by-pass chair nel it, without first beingconverted into pressure. The air delivered by the tan, and the air drawnthrough the bypass channel 14:, are mingled in the outer whirl-chamberat 16, and all of the air is discharged into the casing 4 through theopening 17, its kinetic 'energy having, by this time, been almost whollyconverted into pressure. From the casing 4, the air passes to theoperating parts 6Q or" the machine through suitable ventilatingpassages, which may be disposed in any convenient manner.

The resistance of the channel 9 to the passage of the air may bereduced, and the capacity oi the fan-inlet liter, d, by

nular partitions 11 and 12. These partitions viding the channel 9 withannular curved partitions 18, shown in section. These partitions aresupported in spaced relation in the channel 9 in any convenient manner,for example, by the rods 19.

The structure shown and described may, if desired, be duplicated at theother end of themachine.

The device which T have described makes possible the use of relativelysmall fans for cooling large machines, and also increases the coolingetliciency of the fun, because a large part of the air does not passthrough the fan at all. Therefore, the increase in the temperature ofthe air caused by friction within the fan is greatly reduced. My devicehas the additional advantage that larger generators may be madeself-cooling than is possible with the use of ordinary centrifugal fans.

Since many modifications may be made in my device without departing fromthe spirit and intent or" my invention, it do not wish to be restrictedto the precise structural details which it have shown and described, butit is to be understood that no limitations are to be imposed unlessindicated in the appended claims.

l: claim as my invention:

1. A blower comprising a mounted impeller and a stationary casing forsaid impeller, the said casing embodying air inlet and dischargechambers, a channel receiving fluid discharged from the inipeller andcommunicating with the discharge chamber and a channel. communicatingwith the first named channel and with the inlet chamber whereby air fromsaid inlet chamber is caused to divide and pass rotatably partly throughthe blower and partly l through the last named channel.

2. A blower comprising a rotatably mounted impeller and a stationarycasing for said impeller, the said casing embodying air inlet anddischarge chambers, a channel of varying cross section receiving fluiddischarged from the impeller and communicating with the dischargechamber and a channel communicating with the first named channel andwith the inlet chamber whereby air from said inlet chamber is caused todivide and pass partly through the blower and partly through thelast-named channel. 3. A blower comprising a rotatably mounted impellerand a stationary casing for said impeller, the said casing embody ingair inlet and discharge chambers. an annular channel of varying widthreceiving fluid discharged from the impeller and communicating with thedischarge chamber and a channel communicating with the inlet chamber andopening into the first named channel at an acute angle.

blower coimprising a rotatably mounted impeller and a stationary casingA 4-. Al

for said impeller, the said casing embodying air inlet and dischargechambers, an annular channel of varying width receiving fluid dischargedfrom the impeller and opening into the discharge chamber and a channelcommunicating with the inlet chamber and opening into the first namedchannel at its narrowest pointa 5. A blower comprising a rotatablymounted impeller and a stationary casing for said impeller, the saidcasing embodying air inlet and discharge chambers, an annular channel ofvarying width receiving fluid discharged from the impeller and openinginto the discharge chamber and a channel communicating with the inletchamber and opening into the first named channel at its narrowest pointand at an acute angle.

6. In combination in a fluid translating device, a rotatable impeller, acasing for the impeller, a whirl chamber surrounding the impeller andreceiving the fluid discharged therefrom, a second whirl chambersurrounding the first whirl chamber and'receiving the fluid issuingthereirom, and an inlet between the first and second whirl chambers andcommunicating with the inlet to the impeller for. admiitting additionalfluid to the second whirl chamber. I

7. In combination in a fluid translating device, a rotatable impeller, acasing for the impeller, having an inlet port for delivering fluid tothe impeller, a whirl chamber surrounding the impeller and receiving thefluid discharged therefrom, and a passage for admitting an auxiliarysupply of fluid into said whirl chamber at a point intermediate itsinlet and outlet, said passage communicating with the inlet to theimpeller and being so formed as to direct the flow of fluid issuingtherefrom in substantially the direction of the fluid traversing thewhirl chamber.

8. In combination in a fluid translating device, a rotatable impeller, acasing for the impeller, a stationary whirl chamber surrounding theimpeller and receiving the fluid discharged therefrom, a secondstationary whirl chamber surrounding the first and receiving the fluidissuing therefrom, and an annular fluid admission port communicatingwith the inlet to the impel ler and located between said whirl chambersfor admitting additional fluid to said second chamber, andthe walls ofsaid admission port being so formed as to facilitate an entrainment offluid by the stream of fluid issuing from the first whirl chamber.

In testimony whereof, I have hereunto subscribed my name this 9th day ofJuly, 1914.

HENRY F. SCHMIDT. lVitnesses A. N. FULLERTON, B. B. HINES.

